U.S. patent application number 12/274589 was filed with the patent office on 2009-04-16 for bicycle rear derailleur.
This patent application is currently assigned to SHIMANO INC.. Invention is credited to Takeshi TAKACHI, Etsuyoshi WATARAI.
Application Number | 20090098963 12/274589 |
Document ID | / |
Family ID | 41665508 |
Filed Date | 2009-04-16 |
United States Patent
Application |
20090098963 |
Kind Code |
A1 |
WATARAI; Etsuyoshi ; et
al. |
April 16, 2009 |
BICYCLE REAR DERAILLEUR
Abstract
A bicycle rear derailleur is provided with a base member, a
movable member, a moving mechanism and an angular adjustment
arrangement. The base member includes a first support portion and a
first axle with the first support portion being pivotally mounted
on the first axle. The movable member includes a second support
portion, a chain guide and a second axle with the chain guide being
pivotally mounted on the second support portion by the second axle.
The moving mechanism is coupled between the first and second
support portions. The angular adjustment arrangement is operatively
coupled to either electrically pivot the first support portion
relative to the first axle, or electrically pivot the chain guide
relative to the second support portion when the moving mechanism is
moved to move the second support portion of the movable member
relative to the first support portion of the base member.
Inventors: |
WATARAI; Etsuyoshi; (Osaka,
JP) ; TAKACHI; Takeshi; ( Osaka, JP) |
Correspondence
Address: |
GLOBAL IP COUNSELORS, LLP
1233 20TH STREET, NW, SUITE 700
WASHINGTON
DC
20036-2680
US
|
Assignee: |
SHIMANO INC.
Osaka
JP
|
Family ID: |
41665508 |
Appl. No.: |
12/274589 |
Filed: |
November 20, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11749245 |
May 16, 2007 |
|
|
|
12274589 |
|
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Current U.S.
Class: |
474/80 |
Current CPC
Class: |
B62K 23/06 20130101;
B62M 25/04 20130101; B62M 9/122 20130101; B62M 9/126 20130101; B62M
9/1244 20130101 |
Class at
Publication: |
474/80 |
International
Class: |
B62M 9/12 20060101
B62M009/12; F16H 59/04 20060101 F16H059/04 |
Claims
1. A bicycle rear derailleur comprising: a base member including a
first support portion and a first axle with the first support
portion being pivotally mounted on the first axle; a movable member
including a second support portion, a chain guide and a second axle
with the chain guide being pivotally mounted on the second support
portion by the second axle; a moving mechanism coupled between the
first and second support portions; and an angular adjustment
arrangement operatively coupled to either electrically pivot the
first support portion relative to the first axle, or electrically
pivot the chain guide relative to the second support portion when
the moving mechanism is moved to move the second support portion of
the movable member relative to the first support portion of the
base member.
2. The bicycle rear derailleur according to claim 1, wherein the
moving mechanism includes a pair of links with a drive unit
operatively coupled to at least one of the links.
3. The bicycle rear derailleur according to claim 2, wherein the
drive unit includes an electric motor.
4. The bicycle rear derailleur according to claim 3, wherein the
drive unit further includes a position detecting device that is
arranged to detect a change in relative movement of the second
support portion of the movable member with respect to the first
support portion of the base member due to operation of the
motor.
5. The bicycle rear derailleur according to claim 1, wherein the
angular adjustment arrangement includes an electric motor.
6. The bicycle rear derailleur according to claim 5, wherein the
electric motor is operatively coupled to pivot the first support
portion of the base member relative to the first axle.
7. The bicycle rear derailleur according to claim 6, wherein the
angular adjustment arrangement further includes a gearing
arrangement with a driven gear mounted on the first support portion
of the base member for rotating the first support portion of the
base member relative to the first axle.
8. The bicycle rear derailleur according to claim 6, wherein the
angular adjustment arrangement further includes a position
detecting device that is arranged to detect a change in relative
movement of the first support portion of the base member with
respect to the first axle of the base member due to operation of
the motor.
9. The bicycle rear derailleur according to claim 6, wherein the
moving mechanism includes a pair of links with a drive unit
operatively coupled to at least one of the links.
10. The bicycle rear derailleur according to claim 6, wherein the
drive unit includes an electric motor.
11. The bicycle rear derailleur according to claim 1, wherein the
angular adjustment arrangement includes an electric motor that is
operatively coupled to pivot the chain guide relative to the second
support portion of the movable member.
12. The bicycle rear derailleur according to claim 11, wherein the
chain guide is non-rotatably fixed to the second axle of the
movable member such that the chain guide and the second axle rotate
together; and the angular adjustment arrangement further includes a
gearing arrangement with a driven gear mounted on the second axle
of the movable member for rotating the chain guide relative to the
second support portion of the movable member.
13. The bicycle rear derailleur according to claim 11, wherein the
angular adjustment arrangement further includes a position
detecting device that is arranged to detect a change in relative
movement of the first support portion of the base member with
respect to the first axle of the base member due to operation of
the motor.
14. The bicycle rear derailleur according to claim 11, wherein the
moving mechanism includes a pair of links with a drive unit
operatively coupled to at least one of the links.
15. The bicycle rear derailleur according to claim 11, wherein the
drive unit includes an electric motor.
16. The bicycle rear derailleur according to claim 1, wherein the
moving mechanism includes a pair of links with a first electric
motor operatively coupled to at least one of the links; and the
angular adjustment arrangement includes a second electric motor
operatively coupled to pivot the first support portion of the base
member relative to the first axle, and a third electric motor that
is operatively coupled to pivot the chain guide relative to the
second support portion of the movable member.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention generally relates to a bicycle rear
derailleur. More specifically, the present invention relates to a
bicycle rear derailleur that adjusts an angular position of the
base member and/or an angular position of the chain guide when the
bicycle rear derailleur is shifted.
[0003] 2. Background Information
[0004] Bicycling is becoming an increasingly more popular form of
recreation as well as a means of transportation. Moreover,
bicycling has become a very popular competitive sport for both
amateurs and professionals. Whether the bicycle is used for
recreation, transportation or competition, the bicycle industry is
constantly improving the various components of the bicycle. In
particular, the bicycle transmission has been significantly changed
over the years.
[0005] Derailleur operated bicycle transmissions typically comprise
a plurality of sprockets that rotate with another rotating member
(e.g., the front crank and/or the rear wheel of the bicycle) and a
derailleur that is used to shift a chain among the plurality of
sprockets. Conventional derailleur transmissions were manually
controlled by a hand operated actuator such as a lever or
twist-grip attached to the bicycle handlebar, wherein the
derailleur is connected to the actuator by a Bowden cable.
[0006] Recently, bicycles have been equipped with electrical
components to make riding easier and more enjoyable for the rider.
Some bicycles are equipped with electrically controlled shifting
systems. In particular, in theses electrically controlled shifting
systems, the front and rear derailleurs are provided with motors
that laterally move the chain guide to obtain the various gear
positions. In the case of a rear derailleur, the angular position
of the base member with respect to the frame and the angular
position of the chain guide with respect to the movable member are
adjusted during a gear changing operation by a pair of springs.
While this arrangement generally works quite well, the required
adjustment amount for each gear can vary such that the angular
positions of the base member and the chain guide will not be
optimal for each of the gears.
[0007] In view of the above, it will be apparent to those skilled
in the art from this disclosure that there exists a need for an
improved bicycle rear derailleur. This invention addresses this
need in the art as well as other needs, which will become apparent
to those skilled in the art from this disclosure.
SUMMARY OF THE INVENTION
[0008] One object of the present invention is to provide a bicycle
rear derailleur that that can accurately adjusts an angular
position of the base member and/or an angular position of the chain
guide when the bicycle rear derailleur is shifted.
[0009] The foregoing object can basically be attained by providing
a bicycle rear derailleur that basically comprises a base member, a
movable member, a moving mechanism and an angular adjustment
arrangement. The base member includes a first support portion and a
first axle with the first support portion being pivotally mounted
on the first axle. The movable member includes a second support
portion, a chain guide and a second axle with the chain guide being
pivotally mounted on the second support portion by the second axle.
The moving mechanism is coupled between the first and second
support portions. The angular adjustment arrangement is operatively
coupled to either electrically pivot the first support portion
relative to the first axle, or electrically pivot the chain guide
relative to the second support portion when the moving mechanism is
moved to move the second support portion of the movable member
relative to the first support portion of the base member.
[0010] These and other objects, features, aspects and advantages of
the present invention will become apparent to those skilled in the
art from the following detailed description, which, taken in
conjunction with the annexed drawings, discloses preferred
embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Referring now to the attached drawings which form a part of
this original disclosure:
[0012] FIG. 1 is a side elevational view of a bicycle that is
equipped with a bicycle rear derailleur in accordance with one
embodiment;
[0013] FIG. 2 is a perspective view of the handlebar area of the
bicycle illustrated in FIG. 1, with a pair of control devices
mounted to a straight type of handlebar;
[0014] FIG. 3 is a schematic diagram showing one example of an
arrangement of front and rear sprockets of the bicycle illustrated
in FIG. 1;
[0015] FIG. 4 is an enlarged side elevational view of the rear
derailleur illustrated in FIG. 1 in a position corresponding to the
chain engaging the largest rear sprocket;
[0016] FIG. 5 is an enlarged side elevational view of the rear
derailleur illustrated in FIG. 1 in a position corresponding to the
chain engaging the smallest rear sprocket;
[0017] FIG. 6 is a table illustrating one example of initial values
stored in the memory of the controller at the factory for a
particular component group;
[0018] FIG. 7 is an exploded perspective view of the base member of
the rear derailleur illustrated in FIG. 1;
[0019] FIG. 8 is a perspective view of the motor unit for moving
the linkage of the rear derailleur illustrated in FIG. 1, with the
outside cover removed;
[0020] FIG. 9 is a side elevational view of the motor unit of the
base member for moving the linkage of the rear derailleur
illustrated in FIG. 1, with selected portions removed to show the
drive train of the motor unit of the base member;
[0021] FIG. 10 is an outside elevational view of a part of the
angular adjustment arrangement for the base member;
[0022] FIG. 11 is an inside side elevational view of the part of
the angular adjustment arrangement for the base member illustrated
in FIG. 10;
[0023] FIG. 12 is a cross sectional view of the part of the angular
adjustment arrangement for the base member illustrated in FIGS. 10
and 11 as seen along section line 12-12 of FIG. 11;
[0024] FIG. 13 is an exploded perspective view of selected parts of
the angular adjustment arrangement for the base member illustrated
in FIGS. 10 to 12; and
[0025] FIG. 14 is a front end elevational view of the rear
derailleur with portions of the movably member and portions of the
angular adjustment arrangement for the chain guide shown in cross
section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Selected embodiments of the present invention will now be
explained with reference to the drawings. It will be apparent to
those skilled in the art from this disclosure that the following
descriptions of the embodiments of the present invention are
provided for illustration only and not for the purpose of limiting
the invention as defined by the appended claims and their
equivalents.
[0027] Referring initially to FIG. 1, a bicycle 10 is illustrated
that is equipped with an electronic shifting system in accordance
with a first embodiment. As seen in FIGS. 1 and 2, the electronic
shifting system basically includes a right hand side control device
12, a left hand side control device 14, a motorized rear derailleur
16, a motorized front derailleur 18 and an electronic controller 20
with a microcomputer. Other than the electronic shifting system, as
explained below, the bicycle 10 can be any type of bicycle. Thus,
the parts of the bicycle 10 will not be discussed herein, except
for those parts that will assist in the understating of the
electronic shifting system, in particular, the rear derailleur
16.
[0028] As seen in FIG. 2, the right hand side control device 12 is
a rear electronic shifter that is preferably provided with a rear
derailleur downshift switch 12a, a rear derailleur upshift switch
12b and a rear derailleur mode switch 12c. These switches 12a to
12c are push button type switches that are operatively coupled to
the electronic controller 20. The switches 12a and 12b constitute
an input part for inputting gear shift commands and calibration
commands, while the switch 12c constitutes an input part for
inputting mode commands. The rear derailleur downshift switch 12a
is normally used for downshifting the rear derailleur 16, while the
rear derailleur upshift switch 12b is normally used for upshifting
the rear derailleur 16. The rear derailleur mode switch 12c is used
to change the switches 12a and 12b from a shifting mode to other
modes including, but not limited to, a calibration mode for
calibrating gear positions of the rear derailleur 16.
[0029] As diagrammatically illustrated in FIG. 3, the bicycle 10
also includes a drive train having a set of rear sprockets R1 to R7
mounted to the rear axle of the rear wheel in a conventional
manner, and a set of front sprockets F1 to F3 mounted to the crank
axle in a conventional manner, with a chain 22 operatively coupled
between the rear sprockets R1 to R7 and the front sprockets F1 to
F3 in a conventional manner. The control devices 12 and 14 are
operated by the rider in order to control movement (e.g., perform
gear shifting operations) of the rear and front derailleurs 16 and
18 with respect to the rear sprockets R1 to R7 and the front
sprockets F1 to F3, respectively.
[0030] As seen in FIGS. 4 and 5, the rear derailleur 16 is mounted
to a rear portion of a chain stay of a frame 24. The rear
derailleur 16 is configured such that it can be controlled
electrically. The rear derailleur 16 basically includes a base
member 30, a first or inner link 31, a second or outer link 32, a
movable member 33 and a chain guide 34. The base member 30, the
inner link 31, the outer link 32, the movable member 33 and the
chain guide 34 are pivotally coupled together to form a four-point
linkage (connecting) mechanism. In other words, the links 31 and 32
have first ends pivotally coupled to the base member 30 and second
ends pivotally coupled to the movable member 33 for moving the
chain guide 34 laterally with respect to a center longitudinal
plane of the bicycle 10. The chain guide 34 has a chain cage with
two pulleys for receiving the chain 22. The chain cage of the chain
guide 34 is also pivotally connected to the movable member 33 as
explained below.
[0031] As seen in FIGS. 7 to 9, the rear derailleur 16 is provided
with a motor or drive unit 36 that has a reversible electric motor
40 and a gear reduction arrangement 42. The motor 40 is
electrically coupled to the controller 20 and to a power source
(battery source or a generator) by electrical cords in a
conventional manner. The motor 40 is operatively coupled to at
least one of the links 31 and 32 for moving the movable member 33
and the chain guide 34 laterally with respect to the center
longitudinal plane of the bicycle 10. In this embodiment, the inner
link 31 is non-rotatably fixed to the pivot pin 46 by a flat side
46a at its first end 44. The inner link 31 is rotated by the motor
40 via the gear reduction arrangement 42. Thus, the links 31 and 32
form a moving mechanism for moving the movable member 33 and the
chain guide 34 laterally with respect to the center longitudinal
plane of the bicycle 10 with the motor (drive) unit 36 operatively
coupled to at least one of the links 31 and 32.
[0032] The gear reduction arrangement 42 includes a series of gears
that are meshed together such that the angular velocity of the
output shaft (pivot pin) 46 is reduced compared to the angular
velocity of an output shaft 48 of the motor 40. Preferably, the
motor (drive) unit 36 is provided with a position detecting device
that includes an analog position sensor 50 and a digital position
sensor 52 to determine the position and the amount of angular
movement of the output shaft (pivot pin) 46 by the motor 40.
[0033] The analog position sensor 50 is mounted around the output
shaft 46 of the gear reduction arrangement 42. The output shaft 48
of the motor 40 is provided with the digital position sensor 52.
The position sensors 50 and 52 are electrically coupled to the
controller 20 to provide positioning information for energizing the
motor 40 to the correct position for each gear position. The
position detecting device (e.g., the position sensors 50 and 52)
form a rear derailleur position control mechanism for locating the
lateral position of the chain guide 34 over one of the rear
sprockets R1 to R7. In other words, position detecting device
(e.g., the position sensors 50 and 52) is arranged to detect a
change in relative movement of the movable member 33 with respect
to the base member 30 due to operation of the motor 40. The analog
position sensor 50 is preferably a potentiometer that includes a
stationary electrical contact 50a and a movable electrical brush
50b.
[0034] The analog position sensor 50 forms a mechanical/electrical
position sensing device for detecting a current absolute value of
positioning (rotational) angle of at least one of the movable parts
of the motor unit 36. The digital position sensor 52 forms a
digital position sensing device for detecting both a movement
(rotational) direction of the movable parts of the motor unit 36,
and an amount of rotational movement of at least one of the movable
parts of the motor unit 36. The microcomputer of the controller 20
receives signals from the position sensors 50 and 52 for
determining the gear position and the driving amount of the rear
derailleur 16 during calibration and/or shifting.
[0035] The movable electrical brush 50b is mounted on the output
shaft 46 to rotate therewith such that the movable electrical brush
50b slides along the stationary electrical contact 50a when the
output shaft 46 is rotated in response to operation of the motor
40. The analog position sensor 50 outputs an analog or mechanical
signal that is sent to the controller 20 to indicate the current
position of the drive train of the motor unit 36. Since the output
shaft 46 engages the link 31, the lateral position of the chain
guide 34 can be determined based on the output signals from the
analog position sensor 50.
[0036] The digital position sensor 52 is formed by a position
sensor element or shutter wheel 52a and a photo interrupter 52b.
The photo interrupter 52b is preferably a dual channel photo
interrupter having a light source or LED disposed on one side of
the shutter wheel 52a and a light detector such as a
phototransistor disposed on the other side of the shutter wheel
52a. The shutter wheel 52a is mounted on the output shaft 48 of the
motor 40 so that the shutter wheel 52a rotates with the output
shaft 48 of the motor 40. This rotation of the shutter wheel 52a by
the motor 40 causes the passage of light of LED to phototransistor
to be intermittently blocked, thus producing a digital signal
having a period determined by the rate of rotation of the shutter
wheel 52a. Thus, the shape of the digital signal typically will
have square or rectangular saw tooth configuration with each of the
pulses representing one of a plurality of angular positions of the
output shaft 48. Since the photo interrupter 52b has two channels,
the two digital signals will be produced by the photo interrupter
52b that are out of phase with each other. Thus, the digital
position sensor 52 functions as an intermittent optical sensor that
can detect both the rotational direction and the angular position
of the output shaft 48 of the drive train of the motor 40. The
digital position sensor 52 sends a position signal indicative of an
angular position and rotational direction of the output shaft 48 to
the controller 20.
[0037] The analog position sensor 50 acting as a potentiometer is
suitable for detecting an absolute value of positioning angle
(positioning) of the drive train of the motor 40 when the motor 40
stops rotating (stationary). In the other hand, the photo
interrupter of the digital position sensor 52 is suitable for
detecting a value of rotating and a rotating direction. By using
two types of sensors 50 and 52, it is possible to maintain a
correct and stable gear shifting position for the rear derailleur
16.
[0038] The controller 20 cooperates together with the position
sensors 50 and 52 to constitute a bicycle component position
correcting device in which the microprocessor acting as a
comparison unit compares the current absolute value of the
positioning angle of the drive train (movable parts) of the motor
unit 36 to a pre-stored reference value of the positioning angle of
the drive train (movable parts) of the motor unit 36 in response to
a derailleur gear shift command.
[0039] Referring back to FIGS. 4 and 5, the rear derailleur 16 is
preferably provided with a reversible electric motor 60 for
pivoting the base member 30 with respect to the frame 24 and a
reversible electric motor 62 for pivoting the chain guide 34 with
respect to the movable member 33. The motors 60 and 62 form the
basic components of an angular adjustment arrangement of the rear
derailleur 16. The motors 60 and 62 are electrically coupled to the
controller 20, which selectively energizes the motors 60 and 62 to
correctly adjust the position of the chain guide 34 for gear
position of the rear derailleur 16. Preferably, the motors 60 and
62 are synchronized with the motor 40 such that all three motors
40, 60 and 62 act simultaneously. However, the motors 40, 60 and 62
can be operated the sequentially or with various different
sequences as needed and/or desired. In any event, each of the
motors 40, 60 and 62 are preferably operated each time a shifting
operation occurs.
[0040] As seen in FIG. 6, the operation amounts of the motors 60
and 62 are pre-stored in memory of the controller 20. For example,
as seen in FIG. 6, for each gear position of the rear derailleur
16, the base member 30 has a different pre-stored angular position
with respect to the frame 24, and the chain guide 34 has a
different pre-stored angular position with respect to the movable
member 33. The operation amounts of the motors 60 and 62 can be set
in a variety of ways. For example, the operation amounts of the
motors 60 and 62 can be set based on a manufacturer's model for a
rear sprocket cassette. Alternatively, the operation amounts of the
motors 60 and 62 can be set by inputting the number of sprockets
and the number of teeth per sprocket. The operation of and function
of the motors 60 and 62 will be discussed in more detail later.
[0041] Referring now to FIGS. 10 to 13, the base member 30 includes
a first support portion 64 and a first or B-axle 66. The support
portion 64 is fastened to a hanger portion of a chain stay of the
frame 24 by the B-axle 66. In this embodiment, the B-axle 66 is a
bolt that threads into the hanger portion of the frame 24. The
support portion 64 is pivotally mounted on the B-axle 66 such that
the relative position of the rear derailleur 16 can be adjusted
with respect to the frame 24. In particular, the base member 30 is
provided with a stopper plate 68 that supports the motor 60 with a
gear reduction arrangement 70 and a drive gear 72. The motor 60,
the gear reduction arrangement 70 and the drive gear 72 constitutes
a motor or drive unit. The motor 60 is electrically coupled to the
controller 20, which selectively energizes the motor 60 to turn or
rotate the support portion 64 on the B-axle 66 with respect to the
frame 24.
[0042] Specifically, as seen in FIG. 11, a driven gear 74 is
fixedly mounted to the support portion 64 with a center axis of the
driven gear 74 being coincident with center axis of the B-axle 66.
The driven gear 74 and the support portion 64 rotate together as a
unit on the B-axle 66 when the driven gear 74 is turned. The driven
gear 74 has teeth that mesh with teeth of the drive gear 72. Thus,
operation of the motor 60 rotates the drive gear 72 via the gear
reduction arrangement 70 so that the drive gear 72 rotates at the
appropriate angular velocity. Rotation of the drive gear 72 rotates
the driven gear 74, which also results in the support portion 64
rotating about the B-axle 66. The operation of the motor 60 is
controlled by an electrical signal from the controller 20, which
selectively energizes the motor 60. As explained below, the
rotational movement (i.e., amount of angular movement and direction
of rotation) of the support portion 64 with respect to the frame 24
is preferably synchronized with the gear shifting operation
performed by operating the control device 12 (e.g., pushing either
the downshift switch 12a or the upshift switch 12b).
[0043] As best seen in FIGS. 10 and 11, the stopper plate 68 is
designed to be used with a conventional hanger of a bicycle frame.
The stopper plate 68 is disposed on the B-axle 66 between the
hanger of the frame 24 and the support portion 64 of the base
member 30. The stopper plate 68 remains stationary with respect to
the frame 24. In particular, the stopper plate 68 has an abutment
tab 76 and a fixing screw 78. The abutment tab 76 abuts a first
abutment part 24a of the hanger of the frame 24, while the fixing
screw 78 abuts a second abutment part 24b of the hanger of the
frame 24 to prevent rotational movement of the stopper plate 68
about the B-axle 66.
[0044] As seen in FIGS. 12 and 13, a position detecting device in
the form of an analog position sensor 80 is provided between the
stopper plate 68 and the driven gear 74. In particular, the
position detecting device determines the amount of angular movement
of the support portion 64 of the base member 30 with respect to the
frame 24 by operation of the motor 60. The analog position sensor
80 is mounted around the B-axle 66. The position sensor 80 is
electrically coupled to the controller 20 to provide angular
movement information for supplying power to energize the motor 60
to turn the support portion 64 to the correct position for each
gear position.
[0045] The analog position sensor 80 is preferably a potentiometer
that includes a movable electrical contact 80a and a stationary
electrical brush 80b. The movable electrical contact 80a is mounted
on the driven gear 74 to rotate therewith, while the stationary
electrical brush 80b is mounted on the stopper plate 68. The
stationary electrical brush 80b is cantilevered with respect to the
stopper plate 68 and contacts the movable electrical contact 80a
such that the stationary electrical brush 80b slides along the
movable electrical contact 80a when the driven gear 74 is rotated
in response to operation of the motor 60. The analog position
sensor 80 outputs an analog or mechanical signal that is sent to
the controller 20 to indicate the current angular position of the
support portion 64 about the B-axle 66.
[0046] As seen in FIG. 14, the movable member 33 includes a second
support portion 84 and a second or P-axle 86. The chain guide 34
being pivotally mounted on the support portion 84 by the P-axle 86
such that the relative position of the chain guide 34 can be
adjusted with respect to the support portion 84. In particular, the
chain cage of the chain guide 34 is non-rotatably fixed to one end
of the P-axle 86 of the movable member 33 such that the chain guide
34 and the P-axle 86 rotate together as a unit when the motor 62 is
operated by the controller in response to operation of the control
device 12 (e.g., pushing either the switch 12a or the switch 12b).
In particular, the support portion 84 of the movable member 33
supports the motor 62, which is operatively coupled to a gear
reduction arrangement 90 and a drive gear 92. The motor 62, the
gear reduction arrangement 90 and the drive gear 92 constitutes a
motor or drive unit. The motor 62 is electrically coupled to the
controller 20, which selectively energizes the motor 62 to turn or
rotate the P-axle 86 and the chain guide 34 can be adjusted with
respect to the support portion 84.
[0047] Specifically, as seen in FIG. 14, a driven gear 94 is
fixedly mounted to one of the ends of the P-axle 86. The driven
gear 94 and the P-axle 86 rotate together as a unit on the support
portion 84 when the driven gear 94 is turned by the operation of
the motor 62. The driven gear 94 has teeth that mesh with teeth of
the drive gear 92. Thus, operation of the motor 62 rotates the
drive gear 92 via the gear reduction arrangement 90 so that the
drive gear 92 rotates at the appropriate angular velocity. Rotation
of the drive gear 92 rotates the driven gear 94, which also results
in the P-axle 86 rotating within a recess of the support portion
84. The operation of the motor 62 is controlled by an electrical
signal from the controller 20, which selectively energizes the
motor 62. The rotational movement (i.e., amount of angular movement
and direction of rotation) of the chain guide 34 with respect to
the support portion 84 is preferably synchronized with the gear
shifting operation performed by operating the control device 12
(e.g., pushing either the switch 12a or the switch 12b).
[0048] The motor or drive unit of the chain guide 34 is also
provided with a position detecting device in the form of an analog
position sensor 96. The analog position sensor 96 is provided
between the support portion 84 and the chain cage of the chain
guide 34. In particular, the position detecting device determines
the amount of angular movement of the chain guide 34 with respect
to the support portion 84 by operation of the motor 62. The analog
position sensor 96 is mounted around the P-axle 86. The position
sensor 96 is electrically coupled to the controller 20 to provide
angular movement information for supplying power to energize the
motor 62 to turn the chain guide 34 to the correct position for
each gear position.
[0049] The analog position sensor 96 is preferably a potentiometer
that includes a movable electrical contact 96a and a stationary
electrical brush 96b. The movable electrical contact 96a is mounted
on the chain cage of the chain guide 34 to rotate therewith, while
the stationary electrical brush 96b is mounted on the support
portion 84. The stationary electrical brush 96b is cantilevered
with respect to the support portion 84 and contacts the movable
electrical contact 96a such that the stationary electrical brush
96b slides along the movable electrical contact 96a when the driven
gear 94 is rotated in response to operation of the motor 62. The
analog position sensor 96 outputs an analog or mechanical signal
that is sent to the controller 20 to indicate the current angular
position of the chain guide 34.
[0050] The electronic controller 20 is a processing device that
preferably includes a display, a microcomputer and a position
correction program for correcting the positions of the chain guide
34 using the motors 40, 60 and 62. The electronic controller 20 can
also include other conventional components such as an input
interface circuit, an output interface circuit, and storage devices
such as a ROM (Read Only Memory) device and a RAM (Random Access
Memory) device. The internal RAM of the electronic controller 20
stores statuses of various control data from the position detecting
devices. The internal ROM of the electronic controller 20 stores
the predetermined parameter for various shifting operations. Since
electronic controllers are well known in the bicycle field, the
electronic controller 20 will not be discussed and/or illustrated
in detail herein
General Interpretation of Terms
[0051] In understanding the scope of the present invention, the
term "comprising" and its derivatives, as used herein, are intended
to be open ended terms that specify the presence of the stated
features, elements, components, groups, integers, and/or steps, but
do not exclude the presence of other unstated features, elements,
components, groups, integers and/or steps. The foregoing also
applies to words having similar meanings such as the terms,
"including", "having" and their derivatives. Also, the terms
"part," "section," "portion," "member" or "element" when used in
the singular can have the dual meaning of a single part or a
plurality of parts. As used herein to describe the present
invention, the following directional terms "forward, rearward,
above, downward, vertical, horizontal, below and transverse" as
well as any other similar directional terms refer to those
directions of a bicycle equipped with the present invention.
Accordingly, these terms, as utilized to describe the present
invention should be interpreted relative to a bicycle equipped with
the present invention as used in the normal riding position.
Finally, terms of degree such as "substantially", "about" and
"approximately" as used herein mean a reasonable amount of
deviation of the modified term such that the end result is not
significantly changed.
[0052] While only selected embodiments have been chosen to
illustrate the present invention, it will be apparent to those
skilled in the art from this disclosure that various changes and
modifications can be made herein without departing from the scope
of the invention as defined in the appended claims. Furthermore,
the foregoing descriptions of the embodiments according to the
present invention are provided for illustration only, and not for
the purpose of limiting the invention as defined by the appended
claims and their equivalents.
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